a. Field of the Invention
The present invention relates generally to systems for removal and processing of solid waste material, and, more particularly, to a system for removing wood scraps from a work area and for reducing the scraps to merchandisable wood chips.
b. Related Art
Virtually all woodworking operations generate wood scraps of one form or another. Examples of woodworking operations include lumber mills and cabinet shops, among others, and the scraps that they generate range from mere shavings up to pieces of 2xc3x974 or 2xc3x976 lumber.
In a busy production facility, the wood chips tend to pile up around the cutting area, often interfering with work and creating an unsafe work environment. As a result, the scraps must be removed on a periodic basis, typically by hand or by using a shovel or similar implement. This is, of course, both tedious and wasteful of valuable man-hours.
Furthermore, the wood scraps usually vary greatly in size and shape and are not merchandisable in unprocessed form. If chipped and reduced to a smaller, somewhat uniform size they can be sold for use in playgrounds, livestock stalls, landscaping and other purposes. Most conventional chippers, however, are unable to handle widely different sizes of chips without having to be hand-fed; for example, in some installations the scraps are transported away from the work area by a conveyer or other means and are then fed into a chipper by hand. Moreover, potentially harmful foreign objects, such as rocks and pieces of steel, are often found intermixed with the scraps, and have to be removed by hand in order to avoid causing serious damage to the internal components of conventional chippers.
Thus, while chipping does yield a saleable product, the additional time and labor required in order to transport and hand feed the scraps often renders this option uneconomical, given the relatively low prices which wood chips command in the market. As a result, the scraps from many woodworking facilities are simply burned or disposed of as garbage or solid waste, often at considerable expense.
Compounding this problem, conventional chippers are both expensive and inefficient. For example, one form of chipper, known as a xe2x80x9chammer hogxe2x80x9d, uses a series of moving hammers to splinter and crush the wood scraps. However, by nature of their operation, hammer-hog machines must be heavily constructed and consequently tend to be prohibitively expensive. These machines also require powerful (e.g., a 30+horsepower) motors in order to function properly, so that power consumption and operating costs tend to be excessively high. Still further, conventional hammer hog machines do nothing to address the problems of transporting and feeding the scraps into the machine that has been described above; in some instances, a separate blower has been connected to the hammer hog machine to move the wood chips away from the discharge, but this does not aid in transporting the chips to the machine. Furthermore, the use of a separate blower adds to the complexity and expense of the installation, and the additional motor needed for the blower adds significantly to the already high costs of operating a hammer hog machine.
Accordingly, there exists a need for an apparatus for removing varying sizes of wood scraps from a work area in a quick and efficient manner. Furthermore, there exists a need for such an apparatus that will reduce the scraps to saleable wood chips having a small, substantially uniform size. Still further, there exists a need for such an apparatus that can reliably process wood scraps having a wide variety of sizes and shapes (typically, small to mid-size chips) with less need for manual feeding and handling. Still further, there exists a need for such an apparatus that is able to process a substantially steady flow of wood scraps with minimal clogging or jamming. Still further, there exists a need for such an apparatus that is capable of discharging the processed wood chips into a selected collection area. Still further, there exists a need for such an apparatus in which the internal components have a reduced vulnerability to damage by occasional foreign objects, such as rocks and pieces of steel, in the feed material. Still further, there exists a need for such an apparatus that requires comparatively little power in order to function properly, so as to be able to operate at a reduced cost and with lower energy consumption.
The present invention has solved the problems cited above, and is an apparatus for removing wood scraps from a work area by employing a vacuuming action and then reducing these to wood chips having a saleable consistency and size.
Broadly, the apparatus comprises a chipper section for reducing the scraps to wood chips, and a blower section which generates the vacuum for drawing the scraps into the chipper section, and which then draws the chips from the chipper section and discharges them to a predetermined collection area.
In a preferred embodiment, the apparatus may comprise a combined chipper and blower assembly having the chipper section mounted in fluid communication with an intake side of the blower section. The chipper section may include a chipper grate which is mounted over the intake opening of the blower section, and a rotating cutter blade for reducing the scraps to wood chips as these pass through the grate.
The blower section, in turn, may comprise a blower fan having a plurality of vanes for generating the vacuum, and for discharging the air and wood chips under pressure. The fan may comprise a plurality of rotating vanes that are mounted behind the chipper grate so as to receive the wood chips that pass therethrough. The grate also protects the vanes from damage by harmful debris in the feed material. The blower section may further comprise a tangential discharge chute for receiving the wood chips that are discharged by the vanes.
The chipper blade and the blower fan may be mounted for rotation on a common driveshaft. The driveshaft may take its power from an external source, such as an electric motor or an I/C engine, and may extend substantially coaxially through the blower and chipper sections of the assembly.
The chipper blade may have a stepped configuration in which there are upper and lower blade sections. The upper blade section may have a cutting face with a sharply angled edge for penetrating and cutting the wood scraps and for drawing air and debris towards the chipper grate. The lower blade section may have a cutting face with an only slightly angled edge for shearing the wood scraps as they enter the openings in the chipper grate. The upper and lower blade sections may be provided with corresponding cutting faces on their leading and trailing edges so as to permit reversible mounting of the blade sections.
A stationary anvil plate may be mounted in the chipper section so as to block the wood scraps from rotating freely therein and so as to force the scraps into cutting engagement with the rotating chipper blade. The anvil plate may be mounted so that this can be selectively inverted so as to present a fresh, sharp edge to the chipper blade without having to be replaced.
These and other features and advantages of the present invention will be further understood from a reading of the following detailed description with reference to the accompanying drawings.